This page covers the guidelines for wallpaper seam
repairs.
The materials and techniques discussed, work on most types of wallpaper.
Certain wallpapers require specialized techniques and may require the
services of a wallcovering specialist.

This is a paper-backed vinyl that has been on the wall about five years. Installed using clay wallpaper paste over Professional Vinyl Prep. The sprayed on "builder's flat" paint underneath it all eventually failed as the vinyl dried out, shrunk and tugged at the seams.

1.
Relax the vinyl surface by going over the wallpaper with a generous
amount of hot water two or three times. This will allow the wallpaper
to relax and become more flexible.

2.
Thin Professional Vinyl over Vinyl (VOV) wallpaper adhesive, with
water, to a creamy consistency. Work it into the seams by brushing
back and forth across the seams with a paint brush. Alternately, you
could use border adhesive or other brand of "over vinyl" wallpaper
adhesive.

2a.
Where possible, work the brush under the wallpaper to get the VOV as far into
the loose areas as possible. Notice the bare drywall in the photo. The surface
tension of the wallpaper had pulled the paint right off the drywall.

3. A seam roller also works the paste under the loose material.
Use back and forth & up and down motions. At this point,
you'll have a big swath of VOV up and down the seam area.

4. Use a wallpaper smoother to skim the excess wallpaper
adhesive off the facing of the wallpaper, bottom to top.

5. Wash
your wall well. You don't want to end up with a film of non-removable VOV
when everything dries. Towel dry any excess moisture.

6. At this point, the
material should have returned back to its original size and shape. You can use a heat gun
or blow dryer and a
seam roller to get the VOV to grab everything and stick in place. If
you're unfamiliar with heat guns, use caution, heat can melt the vinyl coating on wallpaper.
Follow up with a cool sponge to set the repair.

7. These are pastel chalks, very handy for coloring seams.
There are numerous other tricks used to hide seams from acrylic paints
found in hobby stores to watercolors.

8. Any seam
area that don't close properly, or that ends up with a slight overlap, can be
made virtually undetectable by rubbing pastel chalk back and forth across the seam.
The chalk will fall
into gaps, or will be picked up
by any protruding edges.

9. Use a
slightly moist rag to wipe down the seam. The pastel chalk will stick to
the seam where it needs to be.

10. This was the worst seam, a wavy double cut under the window and right
over the baseboard heater. It had opened up to an
eighth of an inch and was as brittle as plastic. Where is it now? It
should take approximately 30 minutes per seam.

Information and photography used on this page graciously
provided by Cliff Hayes.